Dense sensor and memory cell arrays comprise dense fields of connection lines. The connection lines are, for example, data or supply lines that are connected to input/output terminals of the memory cells or word lines connecting the gate electrodes of access transistors of the memory cells. Resolution enhancement techniques (RETs) improve the resolution of optical lithographic systems such that evenly spaced parallel line structures may be formed at a pitch exceeding the nominal resolution limit of the lithographic system. The half pitch of the lines in the densest line field that can be achieved by RETs is referred to herein as minimum lithographic feature size “F”.
The gate, supply and data lines of sensor or memory cell arrays are connected to further electrical circuits via connection lines that are provided in a connection plane above or below the line field. The arrays comprise contact structures connecting each single cell or a group of cells to a corresponding connection line in the connection plane. For these contact structures, the resolution enhancement techniques are not applicable to the same degree as for evenly spaced lines. For example, an isolated contact chain which comprises evenly spaced contacts being arranged along a chain axis at a 2F-pitch, but lacking corresponding neighboring structures perpendicular to the chain axis, requires contacts with a length of about 4F to 5F perpendicular to the chain axis and thus consumes more substrate area than a F2-contact would consume.
A need exists for simple and stable methods of manufacturing contact and interconnection arrangements that provide area efficient contact and interconnection arrangements.